Although certain specialized types of emergency parachutes, rescue lines or rescue buoys may be deployed by hand, it is desirable to extend the distance of deployment using propulsion devices.
Pilots of hang gliders and ultralight aircraft have previously used hand-deployed emergency parachutes to rescue the pilot and aircraft in the event of a catastrophic in-flight structural failure. These hand-deployed parachutes were packaged to permit mounting of the parachute and suspension lines on the pilot's person, or on the aircraft, in a position close to the pilot. The parachute canopy and suspension lines could, in an emergency, be deployed as a unit. Typically, the pilot would grasp and throw a deployment bag containing the canopy and suspension lines. The suspension lines were connected to the pilot or the aircraft by a harness, a portion of which was designed to play out during the deployment process. The pilot would hand-throw the deployment bag clear of the aircraft, and thereafter the drag from the airstream would extract the parachute canopy and suspension lines from the deployment bag.
While these devices were functional, they had a number of limitations. Most importantly, hand-deployed emergency parachutes were ineffective below a certain altitude, because of the time required for the pilot to complete the hand deployment sequence, and for the canopy to fully inflate. Further, it was difficult for the pilot, acting in an emergency situation, to propel by hand, the deployment bag in an area clear of the aircraft. In certain situations, the deployment bag would foul on the aircraft structure, rendering the parachute system inoperable.
For these and other reasons, the ballistically deployed emergency parachute was developed. Early models of the ballistically deployed parachutes were of mortar-type construction. An explosive charge was placed in the base of a cylindrical container. An emergency parachute canopy and suspension lines were tightly packed, preferably in a vacuum environment, resulting in a highly compact deployment package. The canopy and lines so packed were then placed in the cylindrical container, separated from the explosive by wadding a plunger, or similar material, to protect the canopy and suspension lines from the heat and ignition of the deployment explosion. A pyrotechnic triggering device, such as a shotgun shell, was used to initiate the explosion. The force of this explosion was sufficient to propel the canopy and its suspension lines in a desired direction well clear of the aircraft. This system was a vast improvement over the hand deployment system, but had several drawbacks. Most significant of the limitations of the motor-type system was the recoil generated by the explosion, which could distort the airframe, and have undesirable effects on the direction of deployment. More benign propulsion techniques were tried for the mortar system, including a system of compressed gas. However, in this configuration, the use of compressed gases was generally unsatisfactory, imparting insufficient propulsion to the parachute canopy package.
The current method for deployment of emergency parachutes includes both the mortar system above described, and a newer, rocket-powered deployment method. In this method, a solid propellant, explosive rocket motor is secured to a rocket body, which, in turn, is secured to the apex of the parachute canopy. The parachute canopy, together with its suspension lines, is pressure-packed in a sealed canister. The rocket is connected to the apex of the apex of the canopy by a line which passes between the lid of the container and the container wall. A pyrotechnic ignitor is used to initiate the rocket ignition. The rocket motor, propelling the rocket assembly rapidly away from the aircraft, and exerting tension on the line to the canopy, simultaneously forces open the lid of the container, and extracts the canopy, apex first. This methodology improves deployment time dramatically. Further, the rocket deployment method does not exhibit the undesirable recoil characteristics of the mortar system.
A significant disadvantage of both the rocket and mortar systems, however, is found in the use of explosive and pyrotechnic materials to initiate the deployment sequence. In addition to the possibility of a misfire, certain environmental factors, such as humidity, may render the explosive materials inoperable. More importantly, transport of these type of volatile materials presents significant obstacles to the manufacturers and retailers thereof. Because of regulatory and statutory restrictions for transport of explosive materials in aircraft, these types of parachute systems must frequently be shipped by ground or sea. If shipped by air, there are significant reporting requirements, and substantial additional costs associated with shipment.
Rocket deployment systems have also been used for the purpose of long distance deployment rescue lines, rescue buoys and the like. These deployment systems share the limitations of rocket systems used for emergency parachutes. Likewise, since the rocket deployment system for emergency rescue lines and the like are discharged by a human operator, there is a risk to the operator of injury from the combustion occurring during the rocket motor ignition.
The within invention eliminates the need for any combustible material in these deployment systems, and accordingly, overcomes the many limitations of pyrotechnic devices.